Spray gun



W. H. RUTTER Nov. 28, 1961 SPRAY GUN 2 Sheets-Sheet 1 Filed. Nov. 6, 1959 mvzn'ron. WILLIAM H. RUTTER ATTYS.

w; H. RUTTER Nov. 28, 1961 SPRAY GUN 2 Sheets-Sheet 2 Filed Nov. 6, 1959 s m R v mm m WT Nu IR U SE United States Patent 3,010,658 SPRAY GUN William H. Rutter, Allentown, Pa., assignor to Electra Chemical Engineering & Mfg. Co., Emmaus, Pa., a corporation of Delaware Filed Nov. 6, 1959, Ser. No. 851,404 3 Claims. (Cl. 239-399) The present invention relates to guns for spraying or wetting agent and catalyst.

An object of the present invention is to provide a gun for applying a urethane foam, as referred to above, wherein the components of the spray material are mixed and united together during the spraying action to be in proper condition for coating the surface being coated, and more particularly wherein the prepolymer and premix are mixed and discharged to provide a urethane foam of a fine uniform cell structure.

Another object of the present invention is the provision of a gun which can be easily and completely dismantled so that the parts may be cleaned or replaced when necessary.

A further object of the present invention is to provide a light weight spray gun which is simply constructed and may be operated and manipulated easily and efficiently by a user.

A still further object of the present invention is to provide a spray gun wherein the components of the material are thoroughly commingled so that a foam having a fine, uniform porous cell structure is produced.

These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth and described with reference to the accompanying drawings, in which: a

FIG. 1 is a perspective view of the spray gun of the present invention;

FIG. 2 is a perspective view of an outer casing member for the spray gun;

FIG. 3 is an enlarged perspective view of the exterior of the premix chamber portion of the present invention;

FIG. 4 is an enlarged perspective view of the prepolymer and air manifold portion of the gun of the present invention with a portion broken away for clarity;

FIG. 5 is a longitudinal sectional view of the gun of the present invention showing the premix, prepolymer and air source connections to the gun; 1

FIG. 6 is a view taken along line 6--6 of FIG. 5;

' FIG; 7 is an enlarged sectional View taken along line 7--7 of FIG. 5 showing the mixing head for the gun;

FIG. 8 is a view taken along line 8-8 of FIG. 7; and

FIG. 9 is a fragmentary sectional view showing another form of mixing chamber for the spray gun of the present invention.

ice

larly to FIG. 1 thereof, reference numeral 10' designates generally the spray gun of the present invention consistingof a body portion'12 and a nozzle 14 having a discharge portion 15 connected to the body portion 12 by a suitable coupling member 16. A cover 17 in the form of a generally cylindrical casing surrounds the body portion 12. A suspension member in the form of a hook 19 is connected to the body to provide a means for suspending the gun.

With reference to FIG. 5 which is a sectional view of the gun showing in detail the internal components of the body portion thereof, the body 12 comprises a premix chamber 18, a prepolymer chamber 20, a mixing chamber 22 and an air chamber 24. Connected to the air, prepolymer and premix chambers are supply connections 26, 28 and 30 respectively and conduits 32, 34 and 36 respectively which connect the chambers with suitable air,

prepolymer and premix supply sources (not shown). The

air, prepolymer and premix materials are preferably delivered under pressure through conduits to the chambers from the supply source.

Referring more specifically to the drawings and particu- As shown in FIG. 1 the handle 37 portion of the gun is defined by rigid conduit sections 38 and 40 intermediate the prepolymer and premix conduits 34 and 36 and the connections 28 and 30 which are secured together by means of a brace or bracket 42. A hand operated control means or trigger 44 is pivotally mounted on the body portion by means of a pin 46 adjacent the handle 37. The trigger 44 has a lateral extension portion 48 which engages the plunger 50 of an electrical switch 51 which when actuated effects operation of the premix and prepolymer supply sources. As shown in FIG. 6 the plunger 50 is normally urged outwardly by means of a coil spring 52 mounted in the switch housing 54 which is mounted on the handle 37 by means of a bracket 56 and screw 58 arrangement which in turn maintains the trigger 44 in the outward position. When the plunger 50 is actuated rearwardly upon movement of the trigger '44 and electrical connection is established between the contacts 60 and 62 which through the electrical lead 64 is suitably connected to the supply source actuators.

With reference to FIGS. 3 and 5, the premix chamber 18 is defined by a generally cylindrical tube which is threaded at its outer end to removably mount a closure cap 72. The inner or discharge end of the tube 70 tapers slightly inwardly at 74 and has a plurality of guide and spacer members 76 spaced about its outer periphery. An

outwardly extending peripheral flange 78 is provided on the tube intermediate the inner end of the tube and the mate1ial-connection'30.- A threaded coupling nut 80 having a threaded stem 82 is slidably positioned on tube 7 0 between the flange 78 and the connection 39. .The premix chamber 18 is mounted in the prepolymer chamber 20 and is spaced from the inner peripheral wall thereof substantially along the entire lengthof the prepolymer chamber 20.

The prepolymer chamber which is defined by a generally cylindrical housing 84 has an inwardly extending shoulder or flange 86 proximate its outer end adjacent the flange 78 and which end is internally threaded to receive the coupling nut 80. The coupling nut'80 is threaded into the threaded portion of the prepolymer housing 84 in engagement with the outwardly extending circumferential flange 78 to position. the prepolymer and premix 3 chambers with respect to each other. Nut 80 is tightened after the tube 70 and housing 84 are secured at connections 23 and 30 to their respective conduits 38 and 40 by means of couplings 90 and 92. The abutment of the nut 80 on the flange 78 with a gasket 81, and the threaded connection to the housing 84 preclude leakage of prepolymer from the chamber. The forward end of the housing 84 has an inwardly extending rib portion 94 with an opening 96 within which the tapered end 74 of the tube 70 is so inserted that the annular protrusions 76 engage the inner peripheral surface of the opening 96 in the housing 84. Accordingly, a restricted discharge opening 98 is' defined intermediate the outer peripheral wall of the tube 70 and the inner peripheral wall of the portion 94. The air chamber 24 is defined by an annularopening in the housing 84 at the discharge end, extending axially thereof adjacent its outer peripheral edge. As shown in FIG. the air conduit 32 is connected to the annular air chamber .24 by means of a coupling 102.

"axially extending bores 108 are formed in the outer periphery of the mixing head 104 which are aligned with the annular air passage way or chamber 24 in the housing 84. Extending outwardly from the socket 106 through the mixing head are a'plurality of bores 110 which are spirally arranged and inclined outwardly at an angle with the longitudinal axis as shown in FIG. 7, so that the materialpassingtherethrough from the mixing chamber 22 is discharged toward the inner peripheral wall of the nozzle. The. spiral outwardly inclined openings 1 efiect 'a cutting of the material and a further mixing thereof after an initial mixing in the chamber 22. Air which is supplied to the annular air passage way through the conduit 32 continuously passes through the axially extending bores 108 of the mixing head, and engages the material in the nozzle adjacent the mixing head and discharges it through thedischarge portion of the n z e na ne p 1 i The mixing head 104 ispreferably formed. of fluoroethylene polymer which has excellent anti-stick properties and makes cleaningvery simple. Additionally the internal portion ofthe' nozzle as well as some of the other elements of the gun may be coated with fluoroethylene polymer so that they also may be easily cleaned when desired.

FIG. 9 illustrates another form or arrangement of mixing chamber constnucted in accordance with the present invention. In this embodiment a series of mixing heads are employed for the-purpose of providing for a more thorough mixing of afprepolym'er and premix and also for the purpose of providing for pouring of the mixed materials as opposed tospraying thereof. As shown in FIG.; 9, an'annular 'spacer 116 is provided which engages over a shoulder 118 formed on the forward end fof themixing head 104 and supports at its outer end another .mixing head120. The second mixing head 120 is rsimilar 'to'the first 104 except that there are no air openings provided'imthe outer periphery thereof. A

' sleeve 122 having an inturned flange 124 at one end which engages over. the shoulder 123' formed on the, nozzle 125 is secured to the forward portion of the body by the coupling 16 which engagesfover ashoulder 126 on the opposite end ofthe sleeve. 7

' In operatiomwhen the user desires touse the gun,

the, trigger144 'is, actuated rearwardly to engage 'the'stem' which inturn effects, through theelectrical switch 51,

actuation of the prepolymer and permix supply sources. The premix and prepolymer enter the body portion of the gun through the conduits 38 and 40 and move toward the socket 106 in the mixing head defining an initial mixing chamber 22 wherein the prepolymer and premix are comingled. Thereafter the mixed materials are forced through the spiral holes 110 in the mixing head which causes further mixing of the material. As the material is discharged from the mixing head into the forward portion of the nozzle, air supplied through the annular chamber 24 in the housing 84 engages the mixed material which results in further mixing and pushes it through the discharge end of the nozzle and breaks it up into a very fine spray. The material as a result of the thorough mixing is characterized by a uniform, porous cell structure. In the embodiment illustrated in FIG. 9, as the material leaves the first mixing chamber, ,it passes through the chamber defined by the spacer through the second mixing chamber by means of the air jet as well as the material behind it pushing it. The material is discharged into another chamber 125 and leaves the forward part of the chamber 125 in a solid stream as opposed to a fine spray. Of course, any number of mixing heads may be used in the embodiment of FIG. 9.

From the foregoing, it is apparent that the present invention provides an improved spray gun which is composed of comparatively few parts which may be easily disassembled for cleaning purposes and rapidly reassembled for use. Additionally, the spray gun of the present invention is extremely light and may be maneuvered about by a user without much ditficulty. Further the particular arrangement of the internal portions of the gun,

"as for example the mixing head, provide for a thorough uniform cell structure when mixing the components form the forward end of said body portion, means defining a generally cylindrical first chamber in said body'having a discharge portion, inlet'means connected to said first I second chamber in said body spaced radially from and concentric with said first chamber and having a discharge portion, inlet means connected to said second chamber 7 through which another of said liquid components passes into said 'second'chamber, said discharge portions having a common discharge point, a mixing head positioned intermediate the discharge portions of said first and second chambers and the nozzle, means defining a socket 'in said mixing head adjacent the discharge portions of means and connectingsaid mixing chamber with said nozzle, and air "discharge means operable to discharge air under pressure into said nozzle into intimate contact with said mixed material only subsequentto its passage.

out of thesecondary mixing means for forcibly ejecting the mixed material through said nozzle.

2; Apparatus in accordance with claim '1 including a plurality of axially extending bores in said mixing head intermediate the outer peripheral wall thereof "and 'theisocket portion, said bores communicating with the air discharge means. I

prises a plurality of generally cylindrical spaced bore openings directed outwardly from the longitudinal axis of said mixing head from said socket portion to said nozzle whereby a liquid fiow from said socket portion through said bore openings is directed into the air flow 5 from said air discharge means.

References Cited in the file of this patent UNITED STATES PATENTS 1,757,023 Smith May 6, 1930 6 Longdin et a1. Jan. 10, 1939 Jones Aug. 17, 1948 Downs Apr. 18, 1950 McMahan May 1, 1951 Sanders et a1. Apr. 14, 1953 Preiswerk et a1. Apr. 9, 1957 Marantz Nov. 19, 1957 FOREIGN PATENTS Great Britain Jan. 10, 1940 

